1. Field of the Invention
The present invention relates in general to stereoscopic photography, and in particular to a novel stereoscopic system and camera which are especially adapted for use by the general photographer.
2. The Prior Art
In the production of lenticular-type stereoscopic photographs by the indirect technique, in which a plurality of two-dimensional views of a scene or object field are taken from a number of horizontally spaced vantage points and combined beneath a lenticular screen to form a composite three-dimensional view of the field, it is important for optimum image quality in the stereoscopic picture that both the two-dimensional and the three-dimensional images be sharply focused. Accordingly, the depth of field provided by the camera used to photograph the object field must be appropriate from the point of view of both two-dimensional photography and three-dimensional photography. The proper depth of field for two-dimensional purposes is of course dependent on the permissible size of the circle of confusion, and, as described in our prior U.S. Pat. No. 3,960,563, the proper three-dimensional depth of field is dependent on the permissible parallax value in the stereoscopic picture between images of the objects at the nearest foreground plane and the farthest background plane. Heretofore, the two-dimensional depth of field and the three-dimensional depth of field have been independently controlled, as, for example, by adjusting the f-number of the camera lens, in the case of two-dimensional photography, and by varying the spacing between photographic vantage points (camera or camera lens locations) or by rearranging the various objects in the scene, in the case of the three-dimensional photography. There has been, however, no provision, short of such independent adjustment, for controlling the two-dimensional and three-dimensional depths of field such that the requirements of both are simultaneously met or for permitting the requirements of both to be readily satisfied in situations where neither the photographic vantage points nor the objects can be moved. This is particularly true in general photography where, for purposes of economy and ease of use, it is desirable to fix the camera lenses in place in the camera housing and to avoid the need for the photographer to rearrange the scene. Moreover, it is quite often the case that locations of some, if not all, of the objects of the scenes typically photographed in general usage are beyond the photographer's control.